Pressure release valve



Sept 19, 1950 A. c. M. MAITLAND ETAL 2,523,036

PRESSURE RELEASE VALVE 2 Sheets-Sheet 1 llz/vezzrbo 1 6 fl.(!.M.HazlZZa1zc&

p 19, 1950 A. c. M. MAITLAND ETAL 2,523,036

PRESSURE RELEASE VALVE Filed April 9, I946 2 Sheets-Sheet 2 INVENTORS A. C. M. Moitlond E. D. Bannister Patented Sept. 19, 1950 I PRESSURE RELEASE VALVE 'Ang-us :Charles Marjoribanks Maitland and Eric Dudley Bannister, Yeovil, England, .assignors 7 1:0 Westland AircraftLimited, Yeovil, England Application April 9, 1946, SerialNo. 660,736

In Great? Britain November 10, 1944 -3 Claims. (01. 98 1 .5)

This invention relates to pressure release valves and ismore particularly, though not exclusively, intended for .release of airfrom an aircraft pres- .sure "cabin when a predetermined differential When the valve opens, the pressure drop in the locality of the-holes '16 .causes a pressure drop in the space. 14, which results in an additional opening force on the valve.

The valve spindle 3 is mounted-within its-giiide pressure is exceeded. 5 4 upon axially operative ball bearings 20 in order I When a release valve opens to relieve pressure to reduce friction. from a contained space, a reduction of load on the The valve operates with a substantially uniform surface of the'valvetakes place owing .to a drop pressure derived from the cabin under all conof pressure near the valve seating caused by the ditions up to the maximum flow for which the velocity of the air passing out of the annulus and valve is intended to deal. the valve therefore tends to close.- If flow is main- According to a further modified arrangement .tained through the contained space a general rise illustrated in Figure 2, in which a practically uniin pressure must take place to keep the-valve open form pressure may be maintained within the and yet compensate for the locally reduced prescabin irrespective of the degree of opening of the sure on the valve head as described. valve, we provide a hollow valve head [2 as in the a Themain object of thepresent invention is to 'previous example, together with a fixed internal provide improved forms of pressure release valves piston-like member H, but in this case instead of Whereinthe aforesaid rise of Pressure upon flow forming the latter as a true piston, we connect it taking place; maybe reduced, eliminated or even to the valve head by a flexible diaphragm I8 to reversed. cause positive seal while allowing for axial move- The invention consists in a pressure release m nt, Valve having features as Set u n t Claims In this example the hole or holes [6 in the inpp d e i ner face of the valve head are partially covered Referring 'to the accompanying diagrammatic by adjustment plates I9. When the valve is j d e n closed, the inner space 14 within the hollow valve Figure 1 is a vertical sectional view of an airhead is in communication with the cabin air adcraft' cabin pressure relieving valve embodying jacent to the valve seating by way of the hole or the p s n invention V i holes [6 and there is thus no load across the inner Figure 2 is a similar view of a modified form face of the valve head, but when the valve opens r and i a the pressure drop in the locality of the holes Figure 3, illustrates raphs representing the causes a pressure drop in the aforesaid space Performance Of t val e Shown in F gure 2. which results in a load on the valve head, which In carrying the invention into effect accordload can'be varied to suit requirements by varyins o on f rm ill s ra y Way f example in ing the number, size and position of the holes. g 1351 pp o a V v r a to atica ly This additional load overcomes friction, spring relieving the pressure o an rc a p eS e rate, etc., and cancels out any remaining back cabin when the differential pressure'exceedsa ressure due to these causes. predetermined fi u We p de a hol ow valve It is preferred that the valve spindle be mounthead l2 and mount within the hollow a fixed pised within its guide upon axially operative ball e member 13 Ser to dividethe hollow bearings both in this modification and in other into two spaces l4, IS. The space M is in conmodifications of the present invention in order stant communication, by means of. one or more. to reduce friction. holes It inthe inner face ofthe valvehead It, The performance of this valve is illustrated in f with the space adjacent to the valve seating '2 Figure 3 in which pressure in pounds per square whilst theother space 15 is, in communication by inch are plotted as ordinates and time in seconds way of holes, 10 and II at both ends of the'hol- I as abscissa. slow valve spindle 3 with staticnpressure within Graph A represents the performance when the the cabin; I rate of fiow of air into and out of a space in the The air within the latter SpaCeeXert a if rm wall of which the valve of Figure 2 is fitted, is p u in e pa '5 between the Piston-li e 400 cu. ft. per minute whilst graph B represents member andflthe, outer surface ofthevalve head the performance when the flow is, increased to I 12 whilst the hole or holes It in the inner surface 600 cu. ft. per minute. f ,of the valve head'ensure that there isno pressure The valve on curve A opens sharply at points A drop across that surface of the valve head. C and D and the pressure in the space falls whilst the, valve closes sharply at the points E and F.

The valve on curve B closessharply at the point C and subsequently remains open. In other Words, the pressure falls as soon as the valve opens and then according to the rate of delivery flow either remains constant at a value such that outflow equals inflow, or rises to the value at which the valve will re-open.

We claim:

1. A pressure release valve comprising a seat, a hollow spindle, a hollow head rigid thereon, a fixed guide member for said spindle, a fixed member in said head having a passage therethrough for slidably receiving said spindle serving to divide the space therein into two compartments, communicating 'means including ports in said spindle on one side of said fixed member between one of said compartments and the static pressure to be released, communicating means including ports in said hollow head on the other side of said fixed member between 20 theother compartment and a point adjacent to the valve seat, and means urging said valve into 1 closed position.

i 2'. A pressure release valve as claimed in claim 1 wherein the valve spindle is carried in axially operative ball bearings in a fixed guide.

3. A pressure release valve as claimed in claim 1 wherein spring means are employed for urging said valve into said closed position.

, ANGUS CHARLES MAJ ORIBANKS MAITLAND.

ERIC DUDLEY BANN'ISTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 95,382 Rochow Sept. 23, 1869 846,059 Schmid Mar. 5, 1907 2,413,027 Maxson Dec. 24, 1946 2,466,779 Pevney Apr. 12, 1949 FOREIGN PATENTS Number Country, Date 19,702 Great Britain Sept. 3, 1907 442,217

Germany Mar. 28, 1927 

